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Trial for production of camel pox vaccine and evaluation of the product
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Abstract: The aim of this study is the production of an attenuated tissue culture camel pox vaccine for controlling the disease or protection of camels against infection. The production and evaluation of this vaccine was applied through the application of the following experiments :
1-Adaption of the “Saudi strain” of camel pox virus in Vero cell line for 18 passages and BHK-21 cell line for 16passages. The results revealed that CPE was clear and complete in the 2 different cell cultures after 3 days post inoculation.
2- Titration of the adapted camel pox virus each in the respective type of cell cultures were log10 5.5 TCID 50/ml and log10 4.5 TCID 50/ml for Vero cells and BHK-21 cells, respectively. Vero Cells proved more reliable for adaptation of camel pox virus and is chosen for the production of the vaccine.
3-Growth kinetics of the tissue culture adapted camel pox virus in Vero cell line was studied at different hours post inoculation to investigate the best time for virus harvestation. Maximum titres were log 10 5.1 TCID50/ml and log10 5.5 TCID50/ml for cell free and cell associated virus at respectively at 72 hours post-inoculation.
4-Histopathological studies in Vero cells inoculated with tissue culture adapted camel pox virus were tested. These studies in Vero cell line revealed that specific intracytoplasmic inclusion bodies appeared at 48 hours post inoculation at poles of the nuclei and piknosis of the nuclei.
5-Peparation of the tissue culture adapted camel pox vaccine using lactalbumin sucrose as a stabilizer and lyophilization by freeze drying were carried out and the vaccine was retitrated in Vero cells. The titre of the produced vaccine in Vero cells was log10 5.5 TCID50 / ml before lyophilization and log 10 4.8 TCID 50/ml after lyophilization.
6-Selection of the field dose of the prepared vaccine was done and the results revealed that 10-1 (Containing 1000 virus particles ) was the dose of choice which gave sufficient protection against challenge with virulent camel pox virus( Egyptian strain) without any post vaccinal reaction.
7-Sterility, safety and potency tests were carried out to evaluate the vaccine. The attenuated vaccine was free from contaminants, safe and potent for field application.
8-Keeping quality test was studied and the storage of the vaccine at -4o C or -20o C did not result in any decrease in the efficiency of the vaccine for 8 months.
9-Camels vaccinated with the selected field dose of camel pox vaccine were challenged one and eight months post-vaccination and the results indicated that the acquired immunity persistedup to 8 months (time of experiment ) i.e. camels were completely protected against virulent camel pox virus, while the controls showed signs of camel pox viral infection.
10-The duration of immunity acquired from vaccination was also tested for 8 months (the duration of the study) and proved that vaccinated animals can resist challenge with the virulent camel pox virus. Studies of the acquired immunity of camels vaccinated with tissue culture attenuated camel pox vaccine was tested by cell mediated immune response and immuno-serological tests revealed that :
a-Cell mediated immune response : The result of lymphocyte transformation technique (measured by MTT assay ) revealed that the lymphocytes increased from the 3rd day in cells with mitogen (PHA) till the 14th day post vaccination. The lymphocytes in the challenged camels was increased from the 2nd day till the 14th day in cells with mitogen (PHA), but in the control ones (no-vaccinated challenges camels ), it was higher than vaccinated challenged camels.
b-Sero-conversion was done on sera collected from camels vaccinated with attenuated camel pox vaccine (post vaccination) then after challenge (post-challenge)
Studies on the collected sera byserum neutralization test double antibody sandwich ELISA (DASE) for detection of the humoral antibody level revealed that the neutralizating antibody level started to appear from the 14th day post vaccination (NI50 of 2.5) increased after that to reach its peak on the 30th day post vaccination (NI50 of 3.1) while post challenge, the level of the antibodies decreased on the 5th day post challenge, then increased to a higher level and reached the peak faster than post vaccination. The control camels which received the virulent virus revealed a level of antibodies which reached the peak slower than the vaccinated camels, in addition to signs of the camel pox viral infection.
In the double antibody sandwich ELISA the titre started to appear from the 14th day post-vaccination at a level of 1585 and reached its peak at the 30th day post vaccination at a titre of ( 3145_, while post challenge, the level of the antibodies decreased by the 5th day post- challenge with a titre of (2528), then increased to a higher level at one month post challenge (2344) and reached the peak faster than post-vaccination. The non-vaccinated control camels after inoculation with the virulent virus have the classical picture of camel pox viral infection.
Finally, the produced tissue culture camel pox vaccine proved to be safe and efficient in protecting camels from pox virus infection.
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| Publication year |
2001
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| Availability location |
معهد بحوث الامصال و اللقاحات البيطرية
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| Availability number |
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| Organization Name |
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| Country |
Egypt
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| Publisher |
Name:
كلية الطب البيطري- جامعة الإسكندرية
Place:
الإسكندرية
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| Author(s) from ARC |
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| External authors (outside ARC) |
أ.د. محمد محب حسن النمر
استاذ الميكروبيولوجيا المتفرغ - كلية الطب البيطري- جامعة الإسكندرية
أ.د. حلمي احمد تركي
استاذ الميكروبيولجي ورئيس قسم الميكروبيولوجيا - جامعة الإسكندرية
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| Agris Categories |
Animal diseases
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AGROVOC
TERMS |
Biological differences.
Camels.
Elisa.
Immunity.
Live vaccines.
Poxviridae.
Vaccines.
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| Proposed Agrovoc |
Camel pox;
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| Publication Type |
PhD Thesis
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